1. Field of the present invention
The present invention relates to photolithography of semiconductors. More particularly, the present invention relates to a siloxane compound capable of improving an etching resistance of a photoresist pattern during plasma oxygen etching, a photoresist composition including the siloxane compound, and a method of forming a pattern using the same.
2. Description of the Related Art
The rapid development of technologies in the fields of information and communication has triggered enhanced manufacturing growth of computers and semiconductor systems, thereby providing an increased demand for semiconductor devices having high integration density, i.e., semiconductor devices having a reduced size and an enhanced performance in terms of speed and storage capacity. To meet the recent trend in the industry, various semiconductor processing technologies, e.g., photolithography, have been employed to improve the degree of integration, the reliability and the response capability of the semiconductor devices.
The conventional photolithography process may include forming a photoresist pattern that is used as an etching mask and transferring the photoresist pattern onto a surface of a semiconductor substrate via etching. Formation of the photoresist pattern may include preparation of a photoresist composition from a chemically amplified resist (CAR). In particular, the photoresist composition may include a photoacid generator (PAG) for generating an acid material upon light irradiation, a polymer that may chemically react with the generated acid material, and a solvent. For example, the photoresist composition may be deposited on the semiconductor substrate to form a photoresist film and, subsequently, to be selectively irradiated with light. The irradiated portions of the photoresist film may generate an acid material and dissolve, while portions of the photoresist film unexposed to light irradiation may form a photoresist pattern on the semiconductor substrate.
In a conventional photoresist pattern formation, a processing error of about 20 nm may be allowable at each side portion of a photoresist pattern, i.e., total processing error of a line width of 40 nm, of a semiconductor device having a line width of about 240 nm. The processing error of the line width of the photoresist pattern may generate a non-uniform line width, i.e., pattern roughness, having rough side surfaces. For example, a photoresist pattern of a 240 nm semiconductor device having a 20 nm processing error may have a pattern roughness of about 8.3%, i.e., 20/240.
However, as the degree of high-integration increases, the line width of the semiconductor device may decrease and, thereby, increase the pattern roughness thereof. For example, a processing error of about 20 nm in a 90 nm semiconductor may trigger a pattern roughness of about 22%. Similarly, a processing error of about 20 nm in a 70 nm semiconductor may trigger a pattern roughness of about 29%.
Accordingly, attempts have been made to form a photoresist composition capable of reducing the pattern roughness of a semiconductor device. For example, a molecular weight or a blocking group of the polymer employed in the conventional photoresist composition may be modified to improve the pattern roughness thereof. However, such polymer modification may alter the physical characteristics thereof, e.g., size, and, thereby, weaken the photoresist composition.
In another attempt to improve the pattern roughness of the conventional photoresist composition, a uni-molecular material, i.e., a material having a uniform molecular structure and weight, instead of a polymer, has been provided in order to increase the solubility and, thereby, uniformity of the conventional photoresist composition. However, use of such uni-molecular material in the conventional photoresist composition may provide an etching resistance that is lower than that of the polymer photoresist, i.e., a photoresist composition having a polymer, thereby providing a weak etching mask during etching.
Accordingly, there exists a need for a photoresist composition capable of providing a low pattern roughness and of exhibiting a high etching resistance.